1. Field of the Invention
This invention relates to a device for the detachable and repeatable accurate clamping in X-, Y- and Z-directions of a first object to a second object. As further examples of the objects being able to be clamped to a machine table are e.g. working tables, fixtures, pallets, tools or similar things.
2. Description of the Invention Background
A plurality of different types of such clamping devices are known and have a plurality of such drawbacks connected with a great number of parts with an exposed position, exposed to pollution and to risks of damages which influences the clamping accuracy and the function security.
In the Swedish patent specification 8302028-8 there is described a device intended to eliminate the drawbacks and solve the problems existing in the previous clamping technique. This later clamping deice has a clamping means with an enlarged head and tightening means which in the clamping position engages the enlarged head of the clamping means and a clamping mechanism operating the tightening means into engagement and out of engagement with the head of the clamping means. This device allows a relatively compact housing, but is limited regarding load in the clamping direction and is sensitive to temperature differences between the two clamped objects. The clamping means in the form of a bolt screwed into the one object, e.g. a pallet, thus means that the height of the pallet depends on the material that is required for taking up the clamping means or the bolt when having the intended load. By this construction there arises large tensile concentrations in the material of the pallet in this area. In order that the tightening means shall not lose their grip of the enlarged head of the clamping means, the heels of the tightening means as well as the contact surface of the head are designed with negative angles or undercuts.
Thus, also this developed form of clamping device has a such drawbacks which cannot be regarded as acceptable for a great repeating accuracy when clamping, as has been mentioned, fixtures, pallets, tools or similar to a working table.